rossberg / hamlet Goto Github PK

The following program should print Hello world!:

structure Foo = struct
  structure Bar = struct
    val x = "Hello"
  end
  val x = 42
  val y = " world!\n"
end
open Foo Foo.Bar;
print (x ^ y);

but HaMLet (exec mode) gives

[loading standard basis library]
[processing open.sml]
structure Bar = struct val x = "Hello" : string end
structure Foo =
  struct
    structure Bar = struct val x = "Hello" : string end
    val x = 42 : int
    val y = " world!\n" : string
  end
val x = 42 : string
val y = " world!\n" : string
open.sml:9.9-9.12: runtime type error: string expected

i.e. the dynamic interpretation of open declaration is buggy with multiple longstrids.

In the manual (and Successor ML), the exprow after where is marked optional.

However, the implementation requires exprow to be non-empty.

https://github.com/rossberg/hamlet/blob/master/doc/README.txt#L8 points to http://www.mpi-sws.org/hamlet/, which says "Page Not Found".

The following program is (correctly) rejected because the pattern is non-exhaustive:

let val { a = SOME f } = { a = SOME (fn x => x) }
in f 1;
   f "x"
end;

But, a slight modification circumvents the exhaustiveness checker and allows the program to compile without a warning:

let val { ... = { a = SOME f } } = { a = SOME (fn x => x) }
in f 1;
   f "x"
end;

The exhaustiveness checker should correctly handle ... pattern.